Liquid crystal display (LCD) devices control transmission/blocking of light (image display on/off) by controlling the alignment of liquid crystal molecules that have birefringence property. For example, liquid crystal molecules are aligned by an alignment film with a rubbed surface which is formed on a face to contact to a liquid crystal layer of a substrate.
Other examples of the method for controlling the alignment of liquid crystal molecules includes multi-domain vertical alignment (MVA) mode, in which the alignment of liquid crystal molecules is controlled by dielectric protrusions provided on an electrode or slits in an electrode as structures for alignment control, without performing an alignment treatment. In MVA mode, the structures for alignment control enable to align liquid crystals in multiple different directions while a voltage is applied to the liquid crystals, even without rubbing treatment on the alignment film. Thus, MVA mode achieves better viewing property than conventional TN mode.
However, the regions with protrusions or slits are likely to have low light transmittance. The regions are allowed to have higher light transmittance by simplifying the arrangement of the structures and increasing the distances between the protrusions or the spaces between the slits. Meanwhile, when the distances between the protrusions or the spaces between the slits are too large, transmission of the tilting of liquid crystal molecules takes a long time. Thus, liquid crystal molecules respond very slowly to application of a voltage necessary for image display to the liquid crystal layer.
For achieving a faster response, a study has been made on a technology of forming a polymer layer on which the tilt direction of liquid crystals is recorded is formed on an alignment film (hereinafter also referred to as polymer sustained alignment (PSA) technology). The polymer layer is formed by injecting a polymerizable monomer-containing liquid crystal composition between substrates, followed by polymerization of the monomer under voltage application (see, for example, Patent Literature 1).
Meanwhile, a photo-alignment technology for achieving better viewing property has recently been studied. This technology enables to control the alignment of liquid crystals in multiple directions under voltage application without rubbing treatment on an alignment film so that excellent viewing property can be achieved. In the photo-alignment technology, optically active materials are used as materials of an alignment film, and the film formed is exposed to light, such as ultraviolet rays, to thereby control the alignment (see, for example, Patent Literature 2).